Use of a compound inactivating the kinase a protein in a composition containg a cosmetically acceptable medium in order to lighten the skin

ABSTRACT

A method of using a compound to lighten the skin by inactivating protein kinase A. The compound may be in a composition with either a pharmacologically or cosmetically acceptable medium. Depending upon the medium and concentration of the compound, the composition may be used either therapeutically or non-therapeutically.

The present invention relates to a novel use of cosmetic active agentsfor lightening the skin.

Most of the commercially available depigmenting cosmetic formulationsare based on kojic acid, arbutin or magnesium ascorbyl phosphate.

The inventors became interested in the development of novel depigmentingactive agents that have better compatibility with the skin than those ofthe prior art. They demonstrated that molecules that inactivate proteinkinase A give rise to a skin depigmentation that was attributed hithertoonly to inhibition of the enzyme phosphorylated tyrosinase.

Accordingly, according to a first aspect, the subject of the inventionis the use of a compound that inactivates protein kinase A in acomposition containing a cosmetically acceptable medium, for lighteningthe skin.

The relationship between the skin-lightening activity and theinactivation of protein kinase A (PKA) may be explained by the followingbiochemical mechanism:

The inhibition of protein kinase A induces reduced activation oftyrosinase, as a result of the reduced conversion of the latter enzymeinto phosphorylated tyrosinase; this reduced activation of tyrosinaseresults in a reduction in melanin synthesis, giving rise to skindepigmentation.

The expression “compound that inactivates protein kinase A” especiallydenotes any compound which, by incubating protein kinase A in thepresence of adenosine triphosphate and a protein that may bephosphorylated, for instance the histone H1, inhibits itsphosphorylation, with a percentage of inhibition of greater than orequal to 10%, more particularly with a percentage of inhibition ofgreater than or equal to 25% and preferably greater than or equal to50%.

A subject of the invention is, more particularly, the use of a compoundof formula (I):

or salts thereof, in which R₁ represents the characterizing chain of asaturated or unsaturated, linear or branched fatty acid containing from3 to 30 carbon atoms, R₂ represents the characterizing chain of an aminoacid and m is between 1 and 50, or a mixture of said compounds offormula (I) or salts thereof, in a composition containing a cosmeticallyacceptable medium, for lightening the skin.

The compound of formula (I) as defined above may be in free acid form orin partially or totally salified form. When the compound of formula (I)is in salified form, the salts are especially alkali metal salts such asthe sodium, potassium or lithium salts, alkaline-earth metal salts suchas the calcium, magnesium or strontium salts; the ammonium salt or thesalt of an amino alcohol, for instance the (2-hydroxyethyl)-ammoniumsalt. They may also be metal salts such as divalent zinc or manganesesalts or trivalent iron, lanthanum, cerium or aluminum salts.

In the description hereinbelow, the expression compound of formula (I)means the compound of formula (I) in free form or in partially ortotally salified form.

The expression “characterizing chain” used to define the radicals R₁ andR₂ denotes the nonfunctional main chain of the fatty acid or of theamino acid under consideration.

Thus, for a fatty acid corresponding to the general formula R₁—C(═O)—OH,the characterizing chain will be the chain represented by R₁.

The subject of the invention is, mainly, the use of a compound offormula (I) as defined above, in which the group R₁—C(═O)— contains from7 to 22 carbon atoms.

R₁—C(═O)— especially represents an octanoyl, decanoyl, undecylenoyldodecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, eicosanoyl,docosanoyl, 8-octadecenoyl, eicosenoyl, 13-docosenoyl,9,12-octadecadienoyl or 9,12,15-octadecatrienoyl radical.

A subject of the invention is, more particularly, the use of a compoundof formula (I) as defined above, in which the fragment R₁—C(═O) ischosen from octanoyl, ω-undecylenoyl, dodecanoyl, hexadecanoyl,8-octa-decenoyl, 13-docosenoyl, 9,12-octadecadienoyl and9,12,15-octadecatrienoyl radicals.

For an amino acid represented by the general formula (IIIa):H₂N—CH(R₂)—C(═O)—OH   (IIIa)and for a cyclic amino acid represented by formula (IIIb):

the characterizing chain will be the chain represented by R₂.

R₂ especially represents the characterizing chain of an amino acidchosen from glycine, alanine, serine, aspartic acid, glutamic acid,valine, threonine, arginine, lysine, proline leucine, phenylalanine,isoleucine, histidine, tyrosine, tryptophan, asparagine, glutamine,cysteine, cystine, methionine, hydroxyproline, hydroxylysine, sarcosineand ornithine.

The subject of the invention is, mainly, the use of a compound offormula (I) as defined above, in which, in at least one of the residues

R₂ represents the characterizing chain of phenyl-alanine, tyrosine,histidine, methionine, cysteine or tryptophan.

A subject of the invention is, more particularly, the use of a compoundof formula (I) as defined above, in which m is a decimal number between1 and 10 and is preferably less than 5.

According to a most particular aspect of the present invention, informula (I) as defined above, m is less than or equal to 2 and is moreparticularly less than or equal to 1.4.

According another most particular aspect of the present invention, informula (I) as defined above, m is equal to 1.

According to another particular variant of the present invention, onlyone compound of formula (I), as defined above, is used in thecomposition containing the cosmetically acceptable medium.

According to another particular variant of the present invention, amixture of compounds of formula (I) as defined above is used, and moreparticularly

-   -   either a mixture of compounds of formula (I) all comprising the        same fragment R₁—C(═O),    -   or a mixture of compounds of formula (I) in which m is equal to        1 and all comprising the same fragment

The compounds of formula (I) are generally obtained by N-acylation ofcompounds of formula (IIIa) or (IIIb) as defined above, or saltsthereof.

When it is a mixture of compounds of formula (I), it is obtained, forexample, by N-acylation of the amino acid mixture resulting from thetotal or partial hydrolysis of proteins of any origin.

These proteins may be of animal origin, for instance collagen, elastin,fish flesh protein, fish gelatin, keratin or casein, of plant origin,for instance, proteins from cereals, flowers or fruit, for instanceproteins derived from soybean, sunflower, oat, wheat, maize, barley,potato, lupin, bean, sweet almond, kiwi, mango or apple; they may alsobe proteins obtained from chorellae (unicellular algae), pink algae,yeasts or silk.

This hydrolysis is performed, for example, by heating a protein placedin an acidic or alkaline medium to temperatures of between 60 and 130°C.

This hydrolysis may also be performed enzymatically with a protease,optionally coupled to an alkaline or acidic posthydrolysis. When m isgreater than 1, R₂ represents one and the same chain or several chainscharacterizing different amino acids, depending on the proteinhydrolyzed and the degree of hydrolysis.

The aminograms of a few proteins of plant origin are given in thefollowing table: TABLE A Origin of the protein (amino acid proportionsexpressed as weight %) Oat Soybean Wheat Sunflower Glycine 6.9 4.2 3.26.2 Alanine 5.9 4.2 2.6 4.8 Serine 5.6 5.1 1.7 5.1 Aspartic acid 16.211.7 3.4 10.6 Glutamic acid 28.3 19.1 37.9 23.6 Valine 2.9 5.0 4.2 4.8Threonine 3.1 3.9 2.7 4.4 Arginine 6.6 7.8 3.7 8.4 Lysine 3.6 6.2 1.93.2 Proline 4.7 5.4 11.7 3.0 Leucine 6.4 8.1 7.1 6.4 Phenylalanine 1.45.0 5.4 4.3 Isoleucine 2.2 4.8 3.7 4.1 Histidine 1.7 2.6 2.4 2.0Tyrosine 1.5 3.5 3.1 2.7 Methionine 1.2 1.2 1.6 1.8 Cysteine/cystine 1.91.5 1.9 1.9 Tryptophan — 1.0 1.0 1.3 Origin of the protein (amino acidproportions expressed as weight %) Lupin Potato Bean Maize Glycine 0.94.8 4.0 2.4 Alanine 2.4 5.0 4.0 7.95 Serine 6.1 5.8 4.9 5.1 Asparticacid 15.8 12.5 10.5 10.6 Glutamic acid 8.0 11.5 16.8 23.6 Valine 7.9 7.14.5 4.8 Threonine 8.1 6.1 3.6 4.4 Arginine 16.1 5.0 9.21 8.4 Lysine 7.17.8 6.5 6.2 Proline — 5.1 4.4 3.0 Leucine 7.45 10.4 7.4 8.1Phenylalanine 8.6 6.4 4.4 4.3 Isoleucine 8.7 6.1 3.9 4.1 Histidine — 2.22.6 2.0 Tyrosine — 5.7 3.6 2.7 Methionine 0.6 2.4 0.8 1.8Cysteine/cystine — 1.6 1.7 1.9 Tryptophan 1.2 1.4 1.2 1.3 Ornithine 0.4— — —

The acylation reaction is known to those skilled in the art. It isdescribed, for example, in the international patent applicationpublished under the number WO 98/09611. It is performed either on anamino acid or on an amino acid mixture. The acylating agent generallyconsists of an activated derivative of a carboxylic acid of formulaR₁C(═O)—OH, such as a symmetrical anhydride of this acid or an acidhalide, for instance the acid chloride or acid bromide. It may alsoconsist of a mixture of activated derivatives of carboxylic acidsderived from natural oils or fats of animal or plant origin, such ascoconut oil, palm kernel oil, palm oil, soybean oil, rapeseed oil, maizeoil, beef tallow, spermaceti oil or herring oil.

A subject of the invention is also a nontherapeutic process for treatingthe skin to lighten it, characterized in that a composition containing acosmetically acceptable medium and an effective amount of at least onecompound that inactivates protein kinase A is applied thereto.

A subject of the invention is also a pharmaceutical composition forperforming a therapeutic skin treatment to lighten it, characterized inthat it contains a pharmaceutically acceptable medium and an effectiveamount of at least one compound that inactivates protein kinase A.

In the compositions defined above, the compound that inactivates proteinkinase A is generally used in an amount of between 0.01% and 10% oftheir weight, more particularly between 0.1% and 5% of their weight andmost particularly between 1% and 5% of their weight.

According to another particular aspect, a subject of the invention isthe use as defined above, characterized in that the compound thatinactivates protein kinase A also inactivates adenylate cyclase.

The relationship between the skin-lightening activity and theinactivation of adenylate cyclase may be explained by the followingbiochemical mechanism:

The inactivation of adenylate cyclase results in reduced conversion ofintracellular ATP into cyclic AMP; the reduction in the level of cyclicAMP results in inhibition of protein kinase A (PKA); the inhibition ofprotein kinase A induces reduced activation of tyrosinase as a result ofthe reduced conversion of said enzyme into phosphorylated tyrosinase;this reduced activation of tyrosinase results in a reduction in melaninsynthesis, giving rise to the skin depigmentation.

The expression “compound that inactivates adenylate cyclase” especiallydenotes, in the context of the present invention, any compound which, byincubation of this enzyme in the presence of adenosine triphosphate,inhibits its conversion into cyclic adenosine mono-phosphate, with apercentage of inhibition of greater than or equal to 10%, moreparticularly with a percentage of inhibition of greater than or equal to25% and preferably greater than or equal to 50%.

The compounds that inactivate adenylate cyclase contained in saidcomposition are more particularly chosen from the compounds of formula(I) as defined above or salts thereof, and most particularly from thecompounds of formula (I) as defined above in which R₁—C(═O) is chosenfrom octanoyl and ω-undecylenoyl radicals and in which, in at least oneof the residues

R₂ represents the characterizing chain of phenylalanine.

A subject of the invention is also a process as defined above,characterized in that a composition containing a cosmetically acceptablemedium and an effective amount of at least one compound that inactivatesprotein kinase A and adenylate cyclase, and also a pharmaceuticalcomposition as defined above, characterized in that it contains aneffective amount of at least one compound that inactivates proteinkinase A and adenylate cyclase, are applied to the skin.

According to another particular aspect, a subject of the invention isthe use as defined above, characterized in that the compound thatinactivates protein kinase A and adenylate cyclase is a compound withaffinity for the melanocyte specific hormone (α-MSH) receptor.

The relationship between the skin-lightening activity and the affinityfor the α-MSH receptor may be explained by the following biochemicalmechanism:

The competition between the hormone α-MSH and the molecule with affinityfor the α-MSH receptor results in a reduced level of binding of saidhormone to the cell receptors; the consequence of this competition is toinhibit the activity of adenylate cyclase, which results in reducedconversion of intracellular ATP into cyclic AMP; the reduction in thelevel of cyclic AMP results in inhibition of the enzyme protein kinase A(PKA); the inhibition of protein kinase A induces reduced activation oftyrosinase as a result of the reduced conversion of said enzyme intophosphorylated tyrosinase; this reduced activation of tyrosinase resultsin a decrease in melanin synthesis, giving rise to skin depigmentation.It is this set of successive inhibitions that bears witness to theα-MSH-antagonist nature of the compounds of the invention.

The expression “compound with affinity for the melanocyte specifichormone, α-MSH, receptor”, in the context of the present invention,denotes any compound which displaces the specific binding of aradioactive ligand, for instance nucleoside diphosphate-α-melanocytespecific hormone ([¹²⁵I]NDP-α-MSH) to the α-melanocyte specific hormone(α-MSH) type 1 receptor, known as the MC1R receptor, with a percentageof inhibition of greater than or equal to 10%, more particularly with apercentage of inhibition of greater than or equal to 25% and preferablygreater than or equal to 50%.

The melanocyte specific hormone antagonists contained in saidcomposition are more particularly chosen from the compounds of formula(I) as defined above, or salts thereof.

A subject of the invention is also a process as defined above,characterized in that a composition containing a cosmetically acceptablemedium and an effective amount of at least one compound that inactivatesprotein kinase A and adenylate cyclase, which is a melanocyte specifichormone antagonist, and also a pharmaceutical composition as definedabove, characterized in that it contains an effective amount of at leastone compound that inactivates protein kinase A and adenylate cyclase,which is a melanocyte specific hormone antagonist, are applied to theskin.

As shown by the following examples, the compounds used in the cosmeticor therapeutic treatments defined above are characterized, unexpectedly,by skin-lightening activity that is higher than that of the compositionsof the prior art. They are thus generally suitable for treatments forlightening the skin, especially by depigmentation, and more particularlyfor removing or attenuating colored marks appearing on elderly skin.

The compositions used in said treatments are generally in the form ofdilute aqueous or aqueous-alcoholic solutions, in the form of simple ormultiple emulsions, such as water-in-oil (W/O), oil-in-water (O/W) orwater-in-oil-in-water (W/O/W) emulsions, in which the oil is of plant ormineral nature, or in the form of powder. They may also be dispersed orimpregnated onto fabric or nonwoven materials, whether they are wipes,paper towels or clothing.

The compositions used in said treatments are administered to theindividual in the conventional forms used in cosmetics and pharmacy;these are more particularly topical, oral or parenteral administrations.

In general, the compounds of formula (I) that inactivate protein kinaseA, possibly adenylate cyclase and possibly melanocyte specific hormoneantagonists, which are used in the invention that is the subject of thepresent patent application, as defined above, are combined with numeroustypes of adjuvants or active principles used in cosmetic formulations,whether they are fatty substances, organic solvents, thickeners, gellingagents, softeners, antioxidants, opacifiers, stabilizers, foamingagents, fragrances, ionic or nonionic emulsifiers, fillers, sequesteringagents, chelating agents, preserving agents, chemical screening agentsor mineral screening agents, essential oils, dyestuffs, pigments,hydrophilic or lipophilic active agents, humectants, for instanceglycerol, preserving agents, dyes, fragrances, cosmetic active agents,mineral or organic sunscreens, mineral fillers, for instance ironoxides, titanium oxides and talc, synthetic fillers, for instance Nylonsand crosslinked or noncrosslinked poly(methyl methacrylate), siliconeelastomers, sericites or plant extracts, or alternatively lipidvesicles, or any other ingredient usually used in cosmetics.

As examples of oils that may be combined with the compound of formula(I), mention may be made of paraffins, isoparaffins, white mineral oils,plant oils, animal oils, synthetic oils, silicone oils and fluoro oils;and more particularly:

-   -   oils of plant origin, such as sweet almond oil, coconut oil,        castor oil, jojoba oil, olive oil, rapeseed oil, groundnut oil,        sunflower oil, wheatgerm oil, maize germ oil, soybean oil,        cottonseed oil, alfalfa oil, poppy oil, pumpkin oil, evening        primrose oil, millet oil, barley oil, rye oil, safflower oil,        candlenut oil, passionflower oil, hazelnut oil, palm oil, shea        butter, apricot kernel oil, beauty-leaf oil, sysymbrium oil,        avocado oil or calendula oil;    -   ethoxylated plant oils;    -   oils of animal origin, such as squalene or squalane;    -   mineral oils, such as liquid paraffin, liquid petroleum jelly        and isoparaffins;    -   synthetic oils, especially fatty acid esters such as butyl        myristate, propyl myristate, cetyl myristate, isopropyl        palmitate, butyl stearate, hexadecyl stearate, isopropyl        stearate, octyl stearate, isocetyl stearate, dodecyl oleate,        hexyl laurate, propylene glycol dicaprylate, esters derived from        lanolic acid, such as isopropyl lanolate, isocetyl lanolate,        fatty acid monoglycerides, diglycerides and triglycerides, for        instance glyceryl triheptanoate, alkylbenzoates, poly-α-olefins,        polyolefins, for instance polyisobutene, synthetic isoalkanes,        for instance isohexadecane or isododecane, perfluoro oils and        silicone oils. Among the silicone oils, mention may be made more        particularly of dimethylpolysiloxanes,        methylphenylpolysiloxanes, silicones modified with amines,        silicones modified with fatty acids, silicones modified with        alcohols, silicones modified with alcohols and fatty acids,        silicones modified with polyether groups, modified epoxy        silicones, silicones modified with fluoro groups, cyclic        silicones and silicones modified with alkyl groups.

As other fatty materials that may be combined with this active agent,mention may be made of fatty alcohols or fatty acids.

Among the thickening and/or emulsifying polymers used in the presentinvention, there are, for example, homopolymers or copolymers of acrylicacid or of acrylic acid derivatives, acrylamide homopolymers orcopolymers, homopolymers or copolymers derived from acrylamide,homopolymers or copolymers of acrylamidomethylpropanesulfonic acid, ofvinyl monomer or of trimethylaminoethyl acrylate chloride, sold underthe names Carbopol™, Ultrez™ 10, Permulen™ TR1, Permulen™ TR2, Simulgel™A, Simulgel™ NS, Simulgel™ EPG, Simulgel™ EG, Luvigel∩ EM, Salcare™SC91, Salcare™ SC92, Salcare™ SC95, Salcare™ SC96, Flocare™ ET100,Hispagel™, Sepigel™ 305, Sepigel™ 501, Sepigel™ 502, Flocare™ ET58 andStabileze™ 06; hydrocolloids of plant or biosynthetic origin, forinstance xanthan gum, karaya gum, carrageenates or alginates; silicates;cellulose and its derivatives; starch and its hydrophilic derivatives;polyurethanes.

Among the waxes that may be used in the context of the presentinvention, examples that may be mentioned include beeswax; carnauba wax;candelilla wax; ouricury wax; Japan wax; cork fiber wax or sugarcanewax; paraffin waxes; lignite waxes; microcrystalline waxes; lanolin wax;ozokerite; polyethylene wax; hydrogenated oils; silicone oils; plantwaxes; fatty alcohols and fatty acids that are solid at roomtemperature; glycerides that are solid at room temperature.

Among the emulsifiers that may be used in the context of the presentinvention, examples that may be mentioned include fatty acids;ethoxylated fatty acids; fatty acid esters of sorbitol; ethoxylatedfatty acid esters; polysorbates; polyglycerol esters; ethoxylated fattyalcohols; sucrose esters; alkylpolyglycosides; sulfated and phosphatedfatty alcohols or mixtures of alkylpolyglycosides and of fatty alcoholsdescribed in French patent applications 2 668 080, 2 734 496, 2 756 195,2 762 317, 2 784 680, 2 784 904, 2 791 565, 2 790 977, 2 807 435 and 2804 432.

As examples of active principles that may be combined with the compoundof formula (I) in order to synergistically potentiate its properties,mention may be made of compounds with lightening or depigmentingactivity, for instance arbutin, kojic acid, hydroquinone, ellagic acid,vitamin C, magnesium ascorbyl phosphate, polyphenol extracts, grapeextracts, pine extracts, wine extracts, olive extracts, pond extracts,N-acyl proteins, N-acyl peptides, N-acylamino acids, partialhydrolyzates of N-acyl proteins, amino acids, peptides, total proteinhydrolyzates, partial protein hydrolyzates, polyols (for instanceglycerol, butylene glycol, etc.), urea, pyrrolidonecarboxylic acid orderivatives of this acid, glycyrrhetinic acid, α-bisabolol, sugars orsugar derivatives, polysaccharides or derivatives thereof, hydroxyacids, for instance lactic acid, vitamins, vitamin derivatives, forinstance retinol, vitamin E and its derivatives, minerals, enzymes,coenzymes, for instance coenzyme Q10, hormones or “hormone-like”substances, soybean extracts, for instance Raffermine™, wheat extracts,for instance Tensine™ or Gliadine™, plant extracts, such as tannin-richextracts, isoflavone-rich extracts or terpene-rich extracts, extracts offreshwater or seawater algae, essential waxes, bacterial extracts,minerals, lipids in general, lipids such as ceramides or phospholipids,active agents with slimming activity, for instance caffeine or itsderivatives, active agents with antimicrobial activity or with purifyingaction on greasy skin, such as Lipacide™ PVB, active agents with anenergizing or stimulatory property, for instance Sepitonic™ M3 orPhysiogényl™, panthenol and its derivatives, for instance Sepicap™ MP,antiaging active agents, for instance Sepilift™ DPHP, Lipacide™ PVB,Sepivinol™ or Sepivital™, moisturizing active agents, for instanceSepicalm™ S, Sepicalm™ VG and Lipacide™ DPHP, “anti-photoaging”antiaging active agents, active agents for protecting the integrity ofthe dermo-epidermal junction, and active agents for increasing thesynthesis of components of the extracellular matrix.

As sunscreens that may be incorporated into the composition according tothe invention, mention may be made of any of those featured in theCosmetic Directive 76/768/EEC amended appendix VII.

According to a final aspect of the present invention, a subject thereofis N-(-ω-undecylenoyl)phenylalanine of formula:

its cosmetic use, pharmaceutical compositions containing it andemulsions characterized in that they have a content thereof of between0.01% and 10% of their weight, more particularly between 0.1% and 5% oftheir weight and most particularly between 1% and 5% of their weight.

The experimental study that follows illustrates the invention without,however, limiting it.

In vitro Evaluation of the Depigmenting Activity ofUndecylenoylphenylalanine

The object of this study was to demonstrate the depigmenting activity ofN-undecylenoylphenylalanine, according to a mechanism involving theantagonist effect of the molecule on the a-melanocyte specific hormone(α-MSH) type 1 receptor, known as the MC1R receptor. This type ofpharmacological receptor is mainly found in the melanocytes.

The control of melanogenesis using this receptor is shown in FIG. 1. Itespecially involves adenylate cyclase, cAMP, protein kinase A andtyrosinase. By binding to the receptor MC1R, α-MSH stimulates the αsubunit of the stimulating protein G (Prot GαS). This protein activatesthe enzyme adenylate cyclase, which converts adenosine triphosphate(ATP) into cyclic adenosine monophosphate (cAMP). The cAMP activates theA protein kinases (PK A), which convert tyrosinase into phosphorylatedtyrosinase, which stimulates melanogenesis.

In a first step, the study thus consisted in evaluating the bindingcapacities of N-undecylenoylphenylalanine to the receptors MC1R, foundin the melanocytes.

In a second step, the effect of N-undecylenoylphenylalanine on theactivities of adenylate cyclase, protein kinase A and tyrosinase wasevaluated.

In a third step, the depigmenting activity ofN-undecylenoylphenylalanine on melanocyte cultures of the B16/F1 linewas determined in vitro by measuring the intracellular and extracellularmelanin contents and by measuring the tyrosinase activity.

In a fourth step, the depigmenting activity ofN-undecylenoylphenylalanine was evaluated in a model of pigmentedreconstructed human epidermides (photo-type IV) in order to test theefficacy of the product under real application conditions (topicalapplication of the formulated product).

The effects of the product were compared with those observed in the caseof various reference depigmenting products, hydroquinone, kojic acid andarbutin.

1—Affinity Study on MC1R Receptors

The affinity of N-undecylenoylphenylalanine, kojic acid and arbutin wascompared.

MC1R receptors are isolated from cell membranes of mouse melanocytes ofthe B16/F1 line via the method described in: Siegrist W., OestreicherM., Stutz M., Girard J. and Eberle A. E.; J. Recep. Res., 8, 1988,323-343”.

N-Undecylenoylphenylalanine, arbutin and kojic acid are diluted to aconcentration of 10 mg/ml in decinormal aqueous sodium hydroxidesolution. They are each tested separately at concentrations of 0.1 mg/mland 1 mg/ml. Sodium hydroxide has no effect on the parameter studied.

The MC1R receptors are incubated, in the presence or absence of theseproducts, with an iodine-125 labeled radioactive ligand, the nucleosidediphosphate-α-melanocyte specific hormone [¹²⁵I]NDP-α-MSH at aconcentration of 0.05 nM, for 90 minutes at 22° C.

Control cultures are incubated, in the absence of product, and in thepresence of the radioactive ligand. Each test is performed intriplicate.

After incubation for 90 minutes, the cell membranes are rapidly filteredand the filters are washed several times with cold buffer. The amount ofradioactive ligand bound to the MC1R receptors is measured using ascintillation counter (Topcount, Packard).

The results given in the table below are the means of the three testsperformed for each of the products. They are expressed as a percentageof specific binding relative to the control group and as a percentage ofinhibition of this binding. Inhibition of specific Activity relative tobinding by the test Test the control products products at 0.1 mg/ml at 1mg/ml at 0.1 mg/ml at 1 mg/ml Arbutin 100.80 ± 0.55  96.30 ± 4.16   0% 3.7% Kojic acid 104.50 ± 1.38 124.00 ± 1.87   0%   0% N-Undecyl-  57.70± 2.38  4.20 ± 0.86 42.3% 95.8% enoylphenyl- alanine

The results demonstrate that at the test concentrations, neither arbutinnor kojic acid, which are the reference depigmenting compounds,displaces the specific binding of the ligand, ¹²⁵I]NDP-α-MSH; incontrast, N-undecylenoylphenylalanine displaces 42% and 96%,respectively, of the binding of [¹²⁵I]NDP-α-MSH to the MC1R receptors.

2—Study of Adenylate Cyclase Activation

The influence of N-undecylenoylphenylalanine, kojic acid and arbutin onthe conversion of ATP into cAMP was compared via a radioimmunologicalassay.

Adenylate cyclase, which converts ATP into cAMP, is extracted from ratbrains via the method described in “Salamon Y., Londos C. and RodbellM.; Anal. Biochem., 58, 1974, 541-548”; it is then activated with 10 μMof forskolin.

N-Undecylenoylphenylalanine, arbutin and kojic acid are diluted to aconcentration of 10 mg/ml in decinormal aqueous sodium hydroxidesolution. They are each tested separately at a concentration of 1 mg/ml.Sodium hydroxide has no effect on the parameter studied.

The activated enzyme is incubated, in the presence or absence of theseproducts, and in the presence of 0.5 mM of ATP, for 30 minutes at 30° C.

Control cultures are incubated, in the absence of product, and in thepresence of ATP. Each test is performed in triplicate.

After incubation for 30 minutes, the amount of cAMP produced isevaluated via a radioimmunological assay performed using a commercialkit; the radioactivity is measured with a scintillation counter(Topcount, Packard), a small radioactivity count reflecting smallactivation of adenylate cyclase.

The results given in the table below are the means of the three testsperformed for each of the products. They are expressed as a percentageof enzymatic activity relative to the control group and as a percentageof inhibition. Enzymatic activity Inhibition of relative to theadenylate cyclase Test products control activity Arbutin 109.7 ± 4.6% 0% Kojic acid  45.0 ± 6.5%  55% N-Undecylenoylphenylalanine −16.0 ±0.5% 100%

The results demonstrate that at 1 mg/ml, whereas arbutin has no effecton this enzyme, kojic acid induces a moderate effect andN-undecylenoylphenylalanine induces total inactivation.

3—Study of Protein Kinase A Activity

The influence of N-undecylenoylphenylalanine, kojic acid and arbutin onthe phosphorylation of tyrosinase with protein kinase A (PK A) wascompared.

Protein kinase A is extracted from bovine brains via the methoddescribed in: “Chijiwa T., Mishima A., Hagiwara M., Sano M., Hayashi K.,Inoue T., Naito K., Shioka T., Hidaka H.; J. Biol. Chem., 265, 1990,5267-5272”. It is then activated with 3 μM of cAMP.

N-Undecylenoylphenylalanine, arbutin and kojic acid are diluted to aconcentration of 10 mg/ml in decinormal aqueous sodium hydroxidesolution. They are each tested separately at a concentration of 1 mg/ml.Sodium hydroxide has no effect on the parameter studied.

The activated enzyme is incubated, in the presence or absence of theseproducts, and in the presence of ³³P-labeled radioactive ATP([γ-³³P]ATP) and 200 μg/ml of histone H₁, for 20 minutes at 30° C.

Control cultures are incubated, in the absence of product, and in thepresence of radioactive ATP and histone H₁. Each test is performed intriplicate.

After incubation for 20 minutes, the amount of ³³P-labeledphosphorylated histone H₁ is measured using a scintillation counter(Topcount, Packard), a small radioactivity count reflecting smallactivation of the protein kinase A.

The results given in the table below are the means of the three testsperformed for each of the products. They are expressed as a percentageof enzymatic activity relative to the control group and as a percentageof inhibition. Enzymatic activity Inhibition of relative to the proteinkinase A Test products control activity Arbutin  90.9 ± 8.4%  9.1% Kojicacid 113.3 ± 5.0%   0% N-Undecylenoylphenylalanine  −0.4 ± 0.3%  100%

The results demonstrate that at 1 mg/ml, N-undecylenoylphenylalaninetotally inhibits the protein kinase A activity, in contrast to kojicacid or arbutin.

4—Study of Phosphorylated Tyrosinase Activity

The influence of N-undecylenoylphenylalanine, hydroquinone, kojic acidand arbutin on the activity of phosphorylated tyrosinase was compared bymeasuring the conversion of L-tyrosine into L-dopa and dopaquinone,which is a colored product that can be quantified via spectrophotometry(at 490 nm).

The tyrosinase used is a commercial product extracted from fungi.

N-Undecylenoylphenylalanine, hydroquinone, arbutin and kojic acid arediluted to a concentration of 10 mg/ml in decinormal aqueous sodiumhydroxide solution. They are each tested separately at concentrations of0.1 mg/ml and 1 mg/ml. Sodium hydroxide has no effect on the parameterstudied.

Tyrosinase at 66.66 IU/ml is incubated, in the presence or absence ofthese products, and in the presence of 0.2 mM of tyrosine, for 10minutes at 37° C.

Control cultures are incubated, in the absence of product, and in thepresence of tyrosinase and L-tyrosine. Each test is performed intriplicate.

After incubation for 10 minutes, the amount of dopaquinone histoneformed is measured using a spectro-photometer at 490 nm.

The results given in the table below are the means of the three testsperformed for each of the products.

They are expressed as IU/1 of tyrosinase activity and as a percentage ofinhibition of the enzymatic activity relative to the control. Percentageof inhibition of tyrosinase activity with the test products relative tothe control Test products at 0.1 mg/ml at 1 mg/ml Hydroquinone 78 80Arbutin 73 80 Kojic acid 76 80 N-Undecylenoylphenylalanine 80 100 

The results demonstrate that at concentrations of 0.1 mg/ml and 1 mg/ml,all the test products significantly inhibit the activity of tyrosinase.However, the inhibitory activity of undecylenoylphenylalanine is greaterthan that of the other test products.

5—Study of the Depigmenting Activity in B16/F1 Melanocyte Cultures

The influence of N-undecylenoylphenylalanine, hydroquinone, kojic acidand arbutin on the production of intracellular melanin and extracellularmelanin, in B16/F1 melanocyte cultures and on the activity ofphosphorylated tyrosinase, was compared.

Mouse melanocytes of the B16/F1 line are inoculated in 96-well cultureplates at a density of 1500 cells/well. The cells are cultured in aculture medium (MCM medium) at 37° C. under a humid atmospherecontaining 5% CO₂. The cells are used at 60% of confluence, i.e. 4 daysafter inoculation.

The MCM medium has the following composition: DMEM medium (Dulbecco'sModified Eagle's Medium) containing 4.5 g/l of glucose supplemented withL-glutamine (2 mM), penicillin (50 IU/ml), streptomycin (50 μg/ml) andfetal calf serum (10% v/v).

N-Undecylenoylphenylalanine is diluted to 4 mg/ml in decinormal aqueoussodium hydroxide solution. It is tested at 40 μg/ml in the MCM medium.Sodium hydroxide has no effect on the parameters analyzed.

Hydroquinone is tested at 5 μg/ml in the MCM medium. Given its toxicity,it is not tested at 40 μg/ml.

Arbutin and kojic acid are tested at 40 μg/ml in the MCM medium.

The melanocyte cultures are incubated in the presence of the testproduct or of the reference products for 72 hours at 37° C., under ahumid atmosphere containing 5% CO₂.

Control cultures are incubated, in the absence of product, in the MCMmedium. These control cultures are prepared on each culture plate.

Each test is performed six times.

5.1—Measurement of the Extracellular Melanin Content

After incubation for 72 hours, the incubation media of the cells (n=6)are taken up and stored at −80° C. until the time of evaluation of theeffects. The extracellular melanin is quantified by spectrophotometry at450 nm. A melanin calibration range is prepared in parallel.

The results are expressed as μg/ml of extracellular melamin and as apercentage of inhibition relative to the control group. ExtracellularInhibition of melanin extracellular (control: melanin Test products 43 ±11 μg/ml) production Hydroquinone at 5 μg/ml  7 ± 1 μg/ml 85% Arbutin at40 μg/ml 23 ± 6 μg/ml 47% Kojic acid at 40 μg/ml 13 ± 2 μg/ml 70%N-Undecylenoylphenylalanine 12 ± 1 μg/ml 72% at 40 μg/ml5.2—Measurement of the Intracellular Melanin Content

After incubation for 72 hours, a portion of the cell carpet (n=3) isrinsed with phosphate-buffered saline (PBS; pH=7.4), the composition ofwhich is as follows: NaCl: 8 g/l, Na₂HPO₄: 1.15 g/l; KH₂PO₄: 0.2 g/l;KCl: 0.2 g/l; CaCl₂: 0.1 g/l; MgCl₂: 0.1 g/l. The intracellular melaninis solubilized by incubation, with stirring, for 30 minutes at roomtemperature in the presence of decanormal sodium hydroxide.

The intracellular melanin is quantified by spectrophotometry at 450 nm.A melanin calibration range is prepared in parallel.

The results are expressed as μg/ml of intracellular melanin and as apercentage of inhibition relative to the control group. Intracellularmelanin Inhibition of obtained intracellular (control: melanin Testproducts 20 ± 4 μg/ml) production Hydroquinone at 5 μg/ml 0.2 ± 0.1μg/ml 100%  Arbutin at 40 μg/ml    16 ± 2 μg/ml 19% Kojic acid at 40μg/ml    17 ± 1 μg/ml 17% N-Undecylenoylphenylalanine    7 ± 3 μg/ml 66%at 40 μg/ml5.3—Measurement of the Phosphorylated Tyrosinase Activity

After incubation for 72 hours, the second portion of the cell carpet(n=3) is rinsed with PBS. The cells are lyzed with Triton™ X100 at aconcentration of 0.1% (w/v) for 30 minutes at room temperature. Theactivity of the endogenous tyrosinase is evaluated by adding 0.1% (w/v)of L-dopa, followed by incubation for 3 hours at 37° C. in the absenceof air and light. The dopaquinone formed by the reaction between thetyrosinase and the L-dopa is measured by spectrophotometry at 450 nm. Acalibration range of purified tyrosinase is prepared in parallel.

The results are expressed as IU/ml of tyrosinase activity and as apercentage of inhibition relative to the control group. Tyrosinaseactivity Inhibition of (control: tyrosinase Test products 9.8 ± 0.3IU/ml) activity Hydroquinone at 5 μg/ml 3.0 ± 0.3 IU/ml 69% Arbutin at40 μg/ml 7.6 ± 1.1 IU/ml 23% Kojic acid at 40 μg/ml 6.8 ± 0.1 IU/ml 31%N-Undecylenoylphenylalanine 3.2 ± 0.6 IU/ml 67% at 40 μg/ml5.4—Measurement of the Intracellular Protein Content

This assay allows the cytotoxicity of the test products to be evaluated.It is performed in cell lysates prepared as described in the precedingparagraph.

The protein assay is performed according to the Coomassie blue methoddescribed by: “Bradford M.; Anal. Biochem., 72, 1976, 248-254”. Themeasurement is performed by spectrophotometry at 640 nm. A bovine serumalbumin (BSA) calibration range is prepared in parallel.

The results are expressed as mg/ml of proteins and as a percentage ofinhibition relative to the control group. Total proteins Inhibition(control: of protein Test products 0.45 ± 0.01) quantity Hydroquinone at5 μg/ml 0.28 ± 0.01 mg/ml 38% Arbutin at 40 μg/ml 0.43 ± 0.01 mg/ml  5%Kojic acid at 40 μg/ml 0.41 ± 0.02 mg/ml 10% N-Undecylenoylphenylalanine0.38 ± 0.01 mg/ml 17% at 40 μg/ml5.5—Results Analysis

After incubation for 72 hours, hydroquinone, tested at 5 μg/ml, inhibitsthe extracellular melanin content by 85%, the intracellular melanincontent by 100% and the tyrosinase activity by 69%, respectively.However, the depigmenting effect of hydroquinone is partly derived fromits cytotoxic effect, since a 38% decrease in the total protein quantityis observed.

Arbutin, tested at 40 μg/ml, inhibits the extracellular melanin contentby 47%, the intracellular melanin content by 19% and the tyrosinaseactivity by 23%, respectively. At this concentration, arbutin has noeffect on the total protein content.

Kojic acid, tested at 40 μg/ml, inhibits the extracellular melanincontent by 70%, the intracellular melanin content by 17% and thetyrosinase activity by 31%, respectively. At this concentration, kojicacid has no significant effect on the total protein content.

N-Undecylenoylphenylalanine, tested at 40 μg/ml, inhibits theextracellular melanin content by 72%, the intracellular melanin contentby 66% and the tyrosinase activity by 67%, respectively. At thisconcentration, N-undecylenoylphenylalanine decreases the total proteincontent by 17%.

N-Undecylenoylphenylalanine thus has depigmenting activity, demonstratedby a concommitant reduction of the intracellular and extracellularmelanin contents and of tyrosinase activity. Unlike that ofhydroquinone, its depigmenting activity is not linked to a cytotoxiceffect. It has higher depigmenting activity than arbutin and kojic acid.

6—Study of the Depigmenting Activity in Reconstructed Human Epidermides

The influence of N-undecylenoylphenylalanine, hydroquinone, kojic acidand arbutin on the production of intracellular melanin and extracellularmelanin, in B16/F1 melanocyte cultures and on the staining ofepidermides, was compared.

Pigmented human epidermides (phototype IV) supplied by Skinethic, of0.63 cm², are reconstructed from a coculture of normal humankeratinocytes (skin of the forearm, 3 year old donor, 2nd passage) andfrom normal human melanocytes (skin of the forearm, 4 year old donor ofphototype IV, 3rd passage). The keratinocyte/melanocyte ratio is 10:1.The cocultures are inoculated onto inert polycarbonate filters. They arecultured for 10 days in the medium supplied by Skinethic, consisting ofMCDB 153 medium supplemented with 5 μg/ml of insulin, 1.5 mM of calciumand growth factors.

For these tests, the products are tested after having been incorporatedinto a cosmetic formulation consisting of an emulsion comprising anaqueous phase, 10% by weight of a fatty phase (Lanol™ 1688), 2% byweight of an emulsifier (Simugel™ EG), 0.5% by weight of preservingagents (0.3% of Sepicide™ HB+0.2% of Sepicide™ CI). After incorporationof the active principle, the formulation is adjusted to pH=5.5.

N-Undecylenoylphenylalanine, arbutin and kojic acid are incorporatedtherein at elevated temperature (75° C.), in a proportion of 1% or 3% byweight per unit volume (w/v).

On account of its toxicity, hydroquinone is incorporated therein at aconcentration of 0.1% by weight per unit volume (w/v).

The epidermides are cultured in 6-well plates containing 1 ml of themedium described above. They are incubated at 37° C. under a humidatmosphere containing 5% CO₂.

The formulations containing the various active principles are applied tothe surface of the epidermides, at a rate of 2 μl/epidermis, using asterile bacteriological inoculator. The application is performed everyday for 4 consecutive days. The incubation medium of the reconstructedepidermides is renewed every day for 4 consecutive days.

Control epidermides are treated with a formulation free of activeprinciple. Each test is performed in duplicate.

6.1—Chromametric Measurement of the Epidermal Pigmentation

Three days after the final topical application, the color of theepidermides is evaluated using a chromameter (Minolta) by measuring thefollowing parameters L*, a* and b*:

-   -   L* is the lightness index. A depigmenting product should        increase this parameter;    -   a* represents the color spectrum from blue to green. A        depigmenting product should reduce this parameter;    -   b*: represents the color spectrum from red to yellow. A        depigmenting product should reduce this parameter.

The results are expressed in arbitrary units (AU) of each parameter andas a percentage of the control group. L* a* b* Control: Control:Control: 41.38 ± 0.69 AU 10.23 ± 0.51 AU 7.54 ± 0.00 AU Test products AU% AU % AU % Hydroquinone  40.59 ± 2.41 −9 10.19 ± 1.21 0 7.73 ± 0.03 +3formulated at 0.1% (w/v) Arbutin formulated  40.48 ± 0.85 +2 10.02 ±0.13 −2 7.64 ± 0.19 +1 at 1% (w/v) Arbutin formulated  41.13 ± 0.54 +1 9.86 ± 0.18 −4 7.73 ± 0.34 +3 at 3% (w/v) Kojic acid  40.11 ± 1.41 +310.90 ± 0.51 +7 7.67 ± 0.03 +3 formulated at 1% (w/v) Kojic acid  41.69± 0.65 0  9.36 ± 1.02 −8 7.13 ± 0.09 −5 formulated at 3% (w/v)N-Undecylenoyl-  41.34 ± 1.15 0  9.01 ± 1.33 −12 5.96 ± 0.42 −21phenylalanine formulated at 1% (w/v) N-Undecylenoyl- 45.228 ± 1.49 +9 8.78 ± 0.52 −14 5.38 ± 0.06 −29 phenylalanine formulated at 3% (w/v)6.2—Measurement of the Intracellular Melanin Content

Three days after the final topical application and after thechromametric measurement, the intracellular melanin is extracted fromthe epidermides by incubation for 45 minutes at 100° C. in Soluene™ 350(200 μl/epidermis), as described in “Ozeki H., Ito S., Wakamatsu K.,Hirobe T.; J. Invest. Dermatol., 105, 1995, 361-366. The samples arecentrifuged for 10 minutes at 10 000 rpm.

The extracted intracellular melamin is measured by spectrophotometry at500 nm. A melanin calibration range is prepared in parallel.

The results are expressed as mg/ml of intracellular melanin and as apercentage of inhibition relative to the control group. Inhibition ofthe amount of Intracellular melanin intracellular Test products(control: 347 ± 2 μg/ml) melanin Hydroquinone  317 ± 0 μg/ml  −9%formulated at 0.1% (w/v) Arbutin 242 ± 46 μg/ml −28% formulated at 1%(w/v) Arbutin 263 ± 16 μg/ml −24% formulated at 3% (w/v) Kojic acid  273± 2 μg/ml −21% formulated at 1% (w/v) Kojic acid 234 ± 19 μg/ml −33%formulated at 3% (w/v) N-Undecylenoylphenylalanine  264 ± 9 μg/ml −24%formulated at 1% (w/v) N-Undecylenoylphenylalanine 264 ± 11 μg/ml −24%formulated at 3% (w/v)6.3—Results Analysis

Hydroquinone, tested in topical application at a concentration of 0.1%(w/v) in an emulsion, has no significant effect either on thechromametric parameters L*, a* and b* or on the melanin content of thereconstructed human epidermides. The absence of a depigmenting effect ofhydroquinone is due either to the low test concentration, which wasdeliberately selected as noncytotoxic, or to the short duration of thetreatment.

Arbutin, tested in topical application at 1% and 3% (w/v) in anemulsion, has no significant effect on the chromametric parameters L*,a* and b*. However, it inhibits the melanin content of the reconstructedhuman epidermides by 28% and 24%, respectively.

Kojic acid, tested in topical application at 1% and 3% (w/v) in anemulsion, has no significant effect on the chromametric parameters L*,a* and b*. However, it inhibits the melanin content of the reconstructedhuman epidermides by 21% and 33%, respectively.

N-Undecylenoylphenylalanine, tested in topical application at 1% (w/v)in an emulsion, inhibits the b* color parameter by 15% and the melanincontent of the reconstructed human epidermides by 24%.

At a concentration of 3% (w/v), N-undecylenoylphenylalanine increasesthe L* parameter by 9% and concomitantly reduces the a* color parameterby 14%, the b* color parameter by 29% and the melanin content of thereconstructed epidermides by 24%.

These tests on reconstructed epidermides show thatN-Undecylenoylphenylalanine has improved depigmenting activity comparedwith that of the reference products, insofar as it has an influence bothon the chromametric parameters and on the intracellular melanincontents.

7—Conclusion

The results obtained in this study together demonstrate strongdepigmenting activity of N-undecylenoylphenylalanine. This activity isquantified both in melanocyte cultures and in a 3D model composed ofreconstructed human epidermides. In contrast to the reference products,the depigmenting activity of N-undecylenoylphenylalanine involves theMC1R receptors. N-Undecylenoylphenylalanine is an MC1R receptorantagonist and inhibits all the steps of the α-MSH cycle involved inmelanogenesis.

COSMETIC FORMULATION EXAMPLES EXAMPLE 2 Lightening Care Emulsion forMature Skin

Montanov ™ 202 02.00% Montanov ™ 68 02.00% Caprylic capric triglycerides10.00% Squalane 10.00% Water q.s. 100% N-Undecylenoylphenylalanine01.00% Sepigel ™ 305 00.70% Magnesium ascorbyl phosphate 02.00%Sepicide ™ HB 00.30% Sepicide ™ CI 00.20% Fragrance 00.50%

EXAMPLE 3 Lightening Firming Care Emulsion

Montanov ™ 202 03.00% 24% sodium hydroxide 00.06% Ethylhexylmethoxycinnamate 06.00% Lanol ™ 1688 08.00% Benzophenone-3 04.00% Waterq.s. 100% N-Undecylenoylphenylalanine 02.00% Simulgel ™ NS 00.50%Sepilift ™ DPHP 00.50% Dimethicone 02.00% Cyclomethicone 02.00% Arbutin 0.3% Sepicide ™ HB 00.30% Sepicide ™ CI 00.20% Fragrance 00.10%

EXAMPLE 4 Lightening Cream-Gel Containing α-Hydroxy Acids

Hydroxyethylcellulose 00.80% Ethylhexyl octanoate 05.00% 60% sodiumlactate 14.00% Water q.s. 100% N-Undecylenoylphenylalanine 03.00%Sepigel ™ 305 04.20% Sepicide ™ HB 02.00% Sepicide ™ CI 03.00% Fragrance00.10%

EXAMPLE 5 Lightening Care Emulsion

Montanov ™ L 01.00% Cetyl alcohol 02.00% Isodecyl neopentanoate 12.00%Cetaryl octanoate 10.00% Glycerol 03.00% Water q.s. 100%N-Undecylenoylphenylalanine 01.00% Simugel ™ EG 02.00% Kojic acid 01.00%Sepicide ™ HB 00.30% Sepicide ™ CI 00.20% Fragrance 00.10%

EXAMPLE 6 Lightening Lotion

Oramix ™ CG110 05.00% Kathon ™ CG 00.08% Water q.s. 100%N-Undecylenoylphenylalanine 01.00% Fragrance 00.10%

This lotion may be sold in bottles or impregnated into wipes.

The definitions of the commercial products used in the examples are asfollows:

Sepilift™ DHP (INCI name: dipalmitoyl hydroxyproline), sold by thecompany SEPPIC.

Sepicide™ HB is a preserving mixture comprising phenoxyethanol, methylparaben, ethyl paraben, propyl paraben and butyl paraben, sold by thecompany SEPPIC.

Sepicide™ CI is imidazolidinylurea, sold by the company SEPPIC.

Sepicalm™ VG (INCI name: sodium palmitoyl proline and extract of waterlily flower), sold by the company SEPPIC.

Kathon™ CG (INCI name:methylisothiazolinone/methylchloroisothiazolinone).

Simulgel™ EG is a copolymer inverse latex (INCI name: sodiumacrylate/sodium acryloyldimethyltaurate copolymer and isohexadecane andPolysorbate 80) sold by the company SEPPIC.

Simulgel™ NS is a copolymer inverse latex (INCI name: hydroxyethylacrylate/sodium acryloyldimethyltaurate copolymer and squalane andPolysorbate 60) sold by the company SEPPIC.

Lanol™ 1688 is cetearyl ethylhexanoate, sold by the company SEPPIC.

Sepigel™ 305 is a polymer inverse latex (INCI name: polyacrylamide andC13-C14 isoparaffin and Laureth 7).

Montanov™ L is an emulsifier based on C14-C22 alcohol and on C12-C20alkyl polyglucoside.

Montanov™ 68 is an emulsifier based on cetearyl alcohol and cetearylpolyglucoside.

Montanov™ 202 is an emulsifier based on arachidyl alcohol, behenylalcohol and arachidyl polyglucoside.

1-26. (canceled)
 27. A method of lightening skin comprising inactivatingthe protein kinase A with a composition comprising: a) a cosmeticallyacceptable medium; and b) a compound.
 28. A method of lightening skincomprising inactivating the protein kinase A with a compositioncomprising: a) a cosmetically acceptable medium; and b) a compound ofgeneral formula (I):

or salts thereof, wherein: 1) R₁ represents the characterizing chain ofa fatty acid comprising: i) about 3 to about 30 carbon atoms; and ii) acharacteristic comprising at least one member selected from the groupconsisting of: aa) saturated; bb) unsaturated; cc) linear; and dd)branched; 2) R₂ represents the characterizing chain of an amino acid;and 3) m is between about 1 and about
 50. 29. The method of claim 28,wherein said compound comprises a radical of general formula (II):R₁—C(═O)—  (II) wherein said radical comprises about 7 to about 22carbon atoms.
 30. The method of claim 29, wherein said radical comprisesat least one member selected from the group consisting of: a) octanoyl;b) decanoyl; c) undecylenoyl; d) dodecanoyl; e) tetradecanoyl; f)hexadecanoyl; g) octadecanoyl; h) eicosanoyl; i) docosanoyl; j)8-octadecenoyl; k) eicosenoyl; l) 13-docosenoyl; m)9,12-octadecadienoyl; and n) 9,12,15-octadecatrienoyl radical.
 31. Themethod of claim 30, wherein said radical comprises at least one memberselected from the group consisting of: a) octanoyl; b) ω-undecylenoyl;c) dodecanoyl; d) hexadecanoyl; e) 8-octadecenoyl; f) 13-docosenoyl; g)9,12-octadecadienoyl; and h) 9,12,15-octadecatrienoyl.
 32. The method ofclaim 31, wherein said R₂ further comprises at least one member selectedfrom the group consisting of: a) glycine; b) alanine; c) serine; d)aspartic acid; e) glutamic acid; f) valine; g) threonine; h) arginine;i) lysine; j) proline leucine; k) phenylalanine; l) isoleucine; m)histidine; n) tyrosine; o) tryptophan; p) asparagine; q) glutamine; r)cysteine; s) cystine; t) methionine; u) hydroxyproline; v)hydroxylysine; w) sarcosine; and x) ornithine.
 33. The method of claim32, further comprising a residue, said residue comprising at least onemember selected from the group consisting of: a) a residue of generalformula (IIIa)—HN—CH(R₂)—C(═O)—  (IIIa), and b) a residue of general formula (IIIb)


34. The method of claim 33, wherein said R₂ comprises at least onemember selected from the group consisting of: a) phenylalanine; b)tyrosine; c) histidine; d) methionine; e) cysteine; and f) tryptophan.35. The method of claim 34, wherein said m is less than about
 5. 36. Themethod of claim 35, wherein said m is less than or equal to about
 2. 37.The method of claim 36, wherein said m is less than or equal to about1.4.
 38. The method of claim 37, wherein said m is equal to about
 1. 39.A method which may be used for treating skin comprising lightening saidskin non-therapeutically with a composition, wherein said compositioncomprises: a) a cosmetically acceptable medium; and b) an effectiveamount of at least one compound that inactivates protein kinase A. 40.The method of claim 39, wherein said composition comprises between about0.01 % and about 10% of its total weight of said compound.
 41. Themethod of claim 40, wherein said composition comprises between about0.1% and about 5% of its total weight of said compound.
 42. The methodof claim 41, wherein said composition comprises between about 1% andabout 5% of its total weight of said compound.
 43. A composition whichmay be used for lightening the skin comprising: a) a pharmaceuticallyacceptable medium; and b) an effective amount of at least one compoundthat inactivates protein kinase A.
 44. The composition of claim 43,wherein: a) said composition is pharmaceutical; and b) said compositionis suitable for therapeutic use.
 45. The method of claim 44, whereinsaid composition comprises between about 0.01 % and about 10% of itstotal weight of said compound.
 46. The method of claim 45, wherein saidcomposition comprises between about 0.1% and about 5% of its totalweight of said compound.
 47. The method of claim 46, wherein saidcomposition comprises between about 1% and about 5% of its total weightof said compound.
 48. The method of claim 27, wherein said compound alsoinactivates adenylate cyclase.
 49. The method of claim 33, wherein: a)said radical comprises at least one member selected from the groupconsisting of: 1) octanoyl radicals; and 2) ω-undecylenoyl radicals; andb) said residue comprises at least one member selected from the groupconsisting of:

wherein said R₂ represents the characterizing chain of phenylalanine.50. The method of claim 48, wherein: a) said radical comprises at leastone member selected from the group consisting of: 1) octanoyl radicals;and 2) ω-undecylenoyl radicals; and b) said residue comprises at leastone member selected from the group consisting of:

wherein said R₂ represents the characterizing chain of phenylalanine.51. The method of claim 42, wherein said compound also inactivatesadenylate cyclase.
 52. The composition of claim 47, wherein saidcompound also inactivates adenylate cyclase.
 53. The method of claim 38,wherein said compound further comprises an affinity for the melanocytespecific hormone (α-MSH) receptor.
 54. The method of claim 51, whereinsaid compound further comprises an affinity for the melanocyte specifichormone (α-MSH) receptor.
 55. The composition of claim 52, wherein saidcompound further comprises an affinity for the melanocyte specifichormone (α-MSH) receptor.
 56. A composition comprisingN-(ω-undecylenoyl)phenylalanine of formula (Ia):


57. The composition of claim 56, wherein said composition is usedcosmetics.
 58. A pharmaceutical composition comprising: a) apharmaceutically acceptable medium; and b) an effective amount of thecompound N-(ω-undecylenoyl)phenylalanine of formula (Ia):


59. A composition comprising an emulsion, wherein said emulsioncomprises between about 0.01% and about 10% of its total weight, thecompound N-(ω-undecylenoyl)phenylalanine of formula (Ia):


60. The composition of claim 59, wherein said emulsion comprises betweenabout 0.1% and about 5% of its total weight of said compound.
 61. Thecomposition of claim 60, wherein said emulsion further comprises betweenabout 1% and about 5% of its total weight of said compound.